Adapting GRUB to boot directly from RAM in protected mode

Adapting GRUB to boot directly from RAM in protected mode

[Patrick Connolly]

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Can anyone think of a straightforward way to modify GRUB to boot a linux
kernel directly from RAM in protected mode?

We have an embedded system with a special BIOS that places a file (any file)
at a fixed location in RAM and executes it (in protected mode) starting at
that same fixed location.  We'd like the file to be a linux kernel (with
boot code) and we're wondering if GRUB could be adapted to do this.  We
realize that some assembly-level modifications would be needed but we aren't
sure how extensive those modifications might be expected to be.

Patrick

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Re: Adapting GRUB to boot directly from RAM in protected mode

[Hollis Blanchard]

On Thu, 2007-02-08 at 11:25 -0800, Patrick Connolly wrote:
> Can anyone think of a straightforward way to modify GRUB to boot a
> linux kernel directly from RAM in protected mode?
> 
> We have an embedded system with a special BIOS that places a file (any
> file) at a fixed location in RAM and executes it (in protected mode)
> starting at that same fixed location.  We'd like the file to be a
> linux kernel (with boot code) and we're wondering if GRUB could be
> adapted to do this.  We realize that some assembly-level modifications
> would be needed but we aren't sure how extensive those modifications
> might be expected to be.  

You should be able to easily write a simple loader for GRUB2. No idea
about GRUB Legacy.

-Hollis

Re: Adapting GRUB to boot directly from RAM in protected mode

[Uwe Hermann]

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Hi,

On Thu, Feb 08, 2007 at 11:25:15AM -0800, Patrick Connolly wrote:
> Can anyone think of a straightforward way to modify GRUB to boot a linux
> kernel directly from RAM in protected mode?
> 
> We have an embedded system with a special BIOS that places a file (any file)
> at a fixed location in RAM and executes it (in protected mode) starting at
> that same fixed location.  We'd like the file to be a linux kernel (with
> boot code) and we're wondering if GRUB could be adapted to do this.  We
> realize that some assembly-level modifications would be needed but we aren't
> sure how extensive those modifications might be expected to be.

You might want to have a look at LinuxBIOS, it seems like it can do what
you want: http://linuxbios.org


HTH, Uwe.
-- 
http://www.hermann-uwe.de  | http://www.holsham-traders.de
http://www.crazy-hacks.org | http://www.unmaintained-free-software.org

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Re: Adapting GRUB to boot directly from RAM in protected mode

[Patrick Connolly]

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Thanks for the suggestion, but changing the BIOS is not an option.  This is
for customer support; it's intended to boot on already-purchased customer
units without changing their unit in any way.

Patrick



On 2/13/07, Uwe Hermann <uwe@hermann-uwe.de> wrote:
>
>
> You might want to have a look at LinuxBIOS, it seems like it can do what
> you want: http://linuxbios.org
>

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